Method of forming hollow metal members



Patented May 1.4, 1940 u METHOD or' FonmNG noLLow METAL Alfred C. Arbogast, Elkhart, Ind., assignor to Northern Indiana Brass Company, Elkhart, Ind., a corporation Application October 22, 1937, Serial No. 170,415

2 Claims. (Cl. 29-157) provide a process for increasing'the thickness of At a suitable state in the process used, the in- 5 a section and changing the shape of a metallic terio 0f the tube 6. 'l is fil-led With a body 0f member .by pressure. Other objects will appear material I6. This material may be of any defrom time to time in the specication and claims. sired nature. For one purpose soft metal may be The invention is illustrated more or less diaused Any material which will sumciently re* grammatically in the accompanying drawing, sisi-compression Ibut is also sufficiently free for 10 wherein: deformation may be used. Figure 1 is a plan view'of one part of a die y When the parts are all in the position of Figfcr carrying out the process of the present inure 1 and both of the dies l, l are in Plane the vention withy parts of the die and the product two die members 8 and I3 are further compressed .shown in section beforethe operation has been to collapse the tube on itself and to force its two 15 carried out; ends together toward eachother. Ihe tube .being Figure 2 is a generally similar view after the filled with the material I6 cannot be collapsed forming operation has been carried out; laterally and hence the material of the tube flows Figure 3 is a section showing an adaptor which and the tube is shortened to the form of Figure is formed by the apparatus of Figures 1 and 2 2 and its walls thickened. As this takes place 20 and subsequent machining; the material is discharged or extruded through Figure 4 is an elevation showing a modified the passage l5 inthe die I3 and may emerge as form of adaptor having ribs made by the appa a wire or rod I1. The size of the passage l5 is ratus and the process of the present invention; made such that the material I6 is discharged Figure 5 is a sectional view generally similar to tllroush it suflieiently rapidly to Permit the dies Figure s, iuustratmg a further modified form of 8 and I3 to move inwardly from the position of 25 adapter; Figure 1 to that of Figure 2, but it is discharged Figure 6 is a transverse sectional view taken at sufficiently slowly to Prevent collapsing of the line 6 6 0f Figure 4 illustrating the part of Figtube 6, lI and thus the material of the tube is ure 4 after the forming operation is complete and Constrained t0 floW longitudinally in the main, so while 1t remains in the (he, that the walls of the tube as they are shortened 30 Like parts are designated by like characters are correspondingly thickened. Thus the tube throughout, the specification and draw-ing at the completion of the movement of thedies,

The numeral l is one of the die members. 1n as Shown in Figure 2 comprises a narrower por- Figures 1 and 2 u; is shown in man, There Wm tion I8, which may be somewhat shorter than the p ordinarily .be two such die members .and they may original narrow portion 1, and a thickened and 35 be of ident-,ical shape, 2 2 are guiding and posishorter portion I9 which is correspondingly much tioning parts engaged by both 0f the die memshorter and much thicker than the original wider bers which serve to keep the proper alignment Portion 5 During the Same operation an annuof the parts. lar ledge or projection 20, may be formed within The shape of the die depends of course, upon the tube. Its formation depending upon the 40 the product that is'to be made. For the product shape and amount 0f travel of the die members illustrated herewith each die has two generally 3 and |3- semi-cylindr-ical cavities 3 which may be reduced The form shown in Figure 4 differs from that as ai; 4, When the two die members l, are put of Figure 3 by the fact that there lare ribs 2| r together they form a cylindrical lcavity 3, and 4 formed on the larger portion I9 and by the fur- 4" having two main diameters and connected by ther fact that an enlarged lip or ange 22 is the shoulder 5. formed on the outer end of the portion I9.

In the particular form illustrated herewith a Dies Suitable for making the form of Figure 4 tube 6, which has a reduced portion 1 is inserted are illustrated in Figure 6 and they comprise two m the le cavity and the die 3 having a, Shoulder dies 23, 23 generally similar to the dies I, I hav- 50 s and a reduced portion lois inserted in the ine oooh a semi-cylinfirloal Cavity 24 shaped as open end 1 of the tube. The reduced portion I0 at 25 to Produce the ribs 'Lflis preferably shouldered as at I I and this shoul- The member Shown 1n Figure 5 is Substantially der is brought, into contact with the open endl of the same as that of Figure 3 except that the inner 55 the reduced portion 1 of the tube. 'Ihe portion annular shoulder 20 is not present and the device I0 may have a perforation or depression I2 is threaded eXterorly. formed in it. The use and operation of the invention are A second die member Il, having a shoulder Il as follows: and a passage or conduit I5, is then inserted in To carry out the invention, dies are prepared 60 This invention relates to a process o! forming metallic articles and particularly to 'a process of increasing the thickness of the section of ametallic member. It has for another purpose to the open end of the die member I. The outer diameter of the die I3 vis greater than the inner .diameter of the portion 6 and hence abuts against its end and does not penetrate it.

of proper shape and size to give to' the article to be manufactured its desired shape. The paranother copper or similar member.

'I'he other portion is thickened to receive a thread which may be internal or external and thus may be readily secured to a member of any material by means of corresponding threads formed on the member to which it is joined. The particular tubular member 6, 1 which is here shown as being formed into the adaptor, may be initially made as'shown with a reduced necklike portion, or may originally be made of a tube having a uniform diameter, a portion of which is subsequently reduced to produce the neck.

Assuming that the dies are prepared, a member such as the tube i, 1 which may be made by drawing, electrolytically or in any other manner, is put into the dies 2, 2. Suitable material I6 is put inside the member which is to be shaped.

This material may be metal or any other material which is of such nature that it will support the tube during the forming operation without permitting undesired distortion of the tube, such as collapsing, folding, and the like, and at the same time it must be sufficiently ductile to be able to escape through the passage l5 readily enough to permit the desired inward movement of one or both of the dies 8, I3. The size of the passage I5 is proportioned to the nature of the material I6, to the travel which is to be given the dies and to the shape which it is desired to give nally to the piece which is being worked upon, and the nature of the material I6 and the size of the passage I5 are thus related to each other and the result must be such that the material I6 escapes sumcientiy rapidly from within the tube 6, 1 to permit proper reforming of the latter and to permit proper movement of the movable die members and at the same time sufiiciently slowly to furnish adequate support to the tubular memberand to prevent undesired distortion of the latter. The material I6 is thus for all practical purposes preferably non-compressible, and at the completion of the operation, as for example as shown in Figure 2, a large proportion of the material I6 has been extruded through the passage I5 from which it may emerge as a. wire or rod-like member I1.

This invention is not limited to any particular type of material I6 nor to any particular shape of die or of article to be nally manufactured. The so-called die or mold within which the tubular or hollow member is positioned may be made in any desired manner of one part or more than one part. As shown, it is indicated as made of two parts clamped together, but this arrangement may be altered.

In carrying out the method of the present invention, the entire tubular portion may be thickened. As shown, however, the portion 1 is not thickened. It is merely compressed and given a greater density of structure, but if desired, this portion might be compressed and thickened just as the portion 6 is thickened and compressed into the portion I9.

During the forming operation carried outin the present invention, the crystals of the metal reorient themselves into a more homogeneous mass and the strength and general physical properties of the article are very much increased because of the pressure exerted upon them during the forming operation. The material I., which is ordinarily soit meta-l, is under pressure and prevents the tube from wrinkling or buckling, and at the same time exerts pressure on the interior of the tube 6, 1, so that the entire body of the tube is subjected to great pressure during the forming operation which, as above noted, not merely reforms the tube but causes a rearrangement of the particles of the metal of which it is formed, which results in a great improvement of the physical properties of the metal. Obviously, machining operations, such as threading, may be readily carried out and the dies may, if desired, be so shaped as to produce ribs, Y

ears and the like, as shown'in Figures 4 and 6.

I claim:

1. The method of cold forming a metallic hollow article having walls of varying thickness, which includes forming a.tubular member, positioning said member in a zone of compression, providing a rigid limiting support for the exterior of said member, positioning in a portion of the interior oi said member a supporting body of a material more extrudable than the material of which the tubular member is formed, rigidly supporting a portion of said tubular member from within, whereby no change within the thickness of said supported portion is'possible, subjecting the opposite ends of said tubular member while cold to endwise pressure and simultaneously subjecting said supporting body to pressure, and thereby substantially shortening and uniformly thickening that portion of the tubular member which is supported by said supporting body while holding it against lateral expansion and, in the course of the subjection of said tubular member and supporting body to such pressure, removing by extrusion a portion of said extrudable supporting body, and controlling said extrusion in such fashion as to maintain at all times a predetermined and adequate support to and pressure against a portion of the interior of said tubular member, while permitting endwise shortening and simultaneous thickening of the portion of said tubular member supported by said supporting body.

2. The method of cold forming a metallic hollow article having walls of varying thickness. which includes forming a hollow member having walls of generally uniform thickness, positioning said member in a zone of compression, providing a rigid limiting support for the exterior of said member to prevent lateral expansion, said support conforming to the desired exterior form of the nished article, positioning in the interior of said member, a supporting body of a material more extrudable than the material of which the hollow member is formed, directing endwise pressure against an end of said hollow member while cold and against the extrudable material contained therein, and thereby shortening said hollow member substantially, and thickening substantially a major portion of the hollow member which is supported by said body of extrudable material, and controlling the escape of said extrudable material and thereby permitting a predetermined and substantially uniform thickening of the portion of the hollow member supported by said material, while preventing any buckling or distortion of said member, other than the shortening and thickening of said portion.

ALFRED C. ARBOGAST. 

